Well your first problem is the 40G won't play SACD's, you need the 80G for that, that was one of the cost cutting things on the lower priced model.

SACD will only play through HDMI

You can use the stock multi AV connector & use the RCA stereo outputs for audio, I think you can go in the setup menu & choose what ever audio output you want.
It will only output 1 audio source at a time if I remember right so if you want to watch a movie using HDMI or Toslink audio you have to change the settings in the menu again.

I'm using HDMI for all my audio on my 60G PS3 including SACD.

To clarify, SACD playback is not available just through HDMI. The PS3 (80, 60, or 20 gig models) will only play back multi-channel SACD via HDMI. 2 channel SACD tracks may be played back via HDMI, analog RCA outputs from the proprietary Multi A/V jack, or as 2 channel downsampled PCM via the digital optical connection (available in the latest firmware update).

Monster Audio makes a good quality Multi A/V connector, with component video plugs and 2 channel RCA audio, and I use it specifically for SACD 2 channel playback. The Multi A/V plug is identical for both PS2 and PS3, so you don't need to spend more for the PS3 version.

I haven't upgraded to a Yamaha receiver with HDMI inputs yet, so my PS3 only has 2 channel SACD playback for now. The PS3 is actually a really good SACD player, so it's worth the effort to set it up for it.